October 11, 2012
Bad News Chemistry: Carbon Dioxide Makes Ice Weaker
An MIT study reveals that carbon dioxide directly reduces the strength of ice, regardless of temperature. Image via Wikimedia Commons/Christof Berger
It’s well established that, in the years to come, increasing amounts of carbon dioxide in the air will cause the climate to change, thereby leading to the ice caps melting at an accelerated rate and worldwide sea level rise. A new scientific finding, though, points at a troubling, entirely separate direct effect of carbon on ice—one that has nothing to do with warming at all.
As documented in a study published yesterday in the Journal of Physics D, researchers from MIT have discovered that merely being in the presence of increased concentrations of carbon dioxide causes ice to significantly weaken, with reduced material strength and fracture toughness, regardless of temperature. With enough carbon dioxide in the air, this alone could make glaciers more likely to split and fracture. Add in the fact that global temperatures will continue to warm—especially around the poles—and the combination of these two factors could mean that the ice caps will melt at even faster rates than experts have previously projected.
“If ice caps and glaciers were to continue to crack and break into pieces, their surface area that is exposed to air would be significantly increased, which could lead to accelerated melting and much reduced coverage area on the earth,” said the study’s lead author, Markus Buehler. “The consequences of these changes remain to be explored by the experts, but they might contribute to changes of the global climate.”
Buehler and his co-author, Zhao Qin, used computer simulations at the atomic level to evaluate the dynamics of ice strength in the presence of various concentrations of carbon dioxide. They found that the gas diminishes the strength of ice by interfering with the hydrogen bonds that hold together the water molecules in an ice crystal. Specifically, at the atomic level, the carbon dioxide competes with the bonded water molecules and, at high enough concentrations, displaces them from the bonds and takes their place.
The carbon dioxide molecules start infiltrating a piece of ice at an outer edge, then slowly split it apart by migrating inward as a crack forms. In doing so, they also attract water molecules outward to the edge by forming bonds with the water molecules’ hydrogen atoms, leaving broken bonds within the crystalline structure and decreasing the ice’s strength overall. The simulations showed that ice that has been infiltrated with carbon dioxide to the point that the gas occupies two percent of its volume is roughly 38 percent less strong.
“In some sense, the fracture of ice due to carbon dioxide is similar to the breakdown of materials due to corrosion, e.g., the structure of a car, building or power plant where chemical agents ‘gnaw’ at the materials, which slowly deteriorate,” Buehler told Environmental Research Web. Since glaciers typically begin to break apart with the formation of small cracks, the researchers say, this could lead to further large-scale fractures, such as the one that recently occurred in Antarctica and produced a fragment larger than New York City.
Because the finding is the first evidence of this phenomenon, it’s too early to say just how much it will accelerate ice melt beyond previous predictions. There are several mechanisms, though, by which it could lead experts to revise upward their estimates for ice melt and sea level rise given a continued increase in greenhouse gas emissions.
In addition to the obvious—that warmer air plus weaker ice means a faster rate of melting—there is the fact that the ice caps play a crucial role in reflecting sunlight back into space. Currently, they cover roughly seven percent of the earth’s surface but are responsible for reflecting 80 percent of the sun’s rays. This is because ice’s bright white color helps it reflect light more efficiently than nearly any other type of ground cover.
If increased carbon dioxide concentrations and warmer temperatures cause ice to melt unexpectedly quickly, though, this bright white ice will be replaced by dark ocean water. More and more sunlight would enter and stay in the atmosphere, thereby causing more and more warming. This positive feedback loop could constitute one of the dreaded “tipping points” that climatologists fear might send our climate on an uncontrolled path towards calamity.
Since the paper only deals with ice at the microscopic level, the next step would be testing the effect of increased carbon dioxide concentrations on ice in a lab setting to check if the effects of the simulated model hold true. Of course, if nothing changes in terms of carbon emissions, we might well have the chance to see if these effects occur on a much larger scale—in the world’s glaciers and polar ice caps.
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IF you look at this article then CO2 needs to make up 2% of the total ice volume to weaken it. This is impossible to do considering CO2 in the atmosphere is only 395 PPM. It is ONLY increasing at 2 PPM every ten years! By the time it could increase even to 450 PPM at this rate then Crude oil AND natural Gas will have severely declined in production or will have become a luxury item only used by a few countries. Even easy to mine coal will have been exhausted. There will be 12 billion people by then cooking with firewood again. Geologically speaking Human Culture as we know it will wink out in a flash, WAY before higher Ocean levels are going to be an issue.
“It’s well established that, in the years to come, increasing amounts of carbon dioxide in the air will cause the climate to change, thereby leading to the ice caps melting at an accelerated rate and worldwide sea level rise. ”
It’s hard to take seriously an article that starts with the above sentence.
1700 billion metric tons of CH4 lays in methane ice and as free gas in sediment on shallow sea floor of East Siberian Arctic Shelf vulnerable to heat increase and disturbance. Let’s hope the weakening of water ice bonds with CO2 rise of atmosphere isn’t going to have destabilizing effect on methane ice better known as methane hydrate. I like the comparison of the way CO2 facilitates weakening of water ice to that of rust or corrosion of metal. Let’s hope the land based ice masses of Greenland and Antarctica resist decay.
Let’s hope the world wakes up to the present danger and acts.
Let’s create an open system of human endeavor to match Nature.. Let’s make an adjustment by tapping writ of law known as ‘Act of God’ so value of money reflects value of its use toward goal of keeping Earth alive. -People too.
Pertaining to Keith’s comment #1: CO2 levels in atmosphere are rising much faster than Keith claims. They are rising almost 2ppm per yr not decade. And local concentration particularly in North have been measured 400ppm.
If I’m not mistaken rise of CO2 at past extinction events was on order of ppm per century or thousand year period not yearly events as we have created by burning up Earth’s easy to get at sequestered carbon for energy or enabler of consumer lifestyle.
Also In Keith’s error of logic about ‘impossibility’,'ONLY’ and
Affinity of ice surface for CO2 could raise expressed harm to strength of the material and raise bubble concentration.
Error of logic and oversimplification and down right fabrication of untruth don’t often happen in isolation but rather in groups that tend to play off each other for support.. It is hard to counter grouped errors in short fashion. But somethings need doing sometimes.. Even if stressful.. Even if it seems futile. But thee is a quote by Einstein who said things need to be expressed as simple as possible not simply simple.. Saving Earth needs clarity.
Dale (#4), you make good points. I would add that Keith’s first sentence: “IF you look at this article then CO2 needs to make up 2% of the total ice volume to weaken it.” is not even true.